The invention relates to sleeve bearing assemblies for fractional or sub-fractional horsepower electric motors and more particularly to self-aligning, floating bearings for use in such motors.
It is known to use sleeve bearings to support the rotating shaft of fractional and sub-fractional horsepower motors. The sleeve bearings typically include a tubular bore for accepting and supporting the shaft. To compensate for variations in shaft angle during rotation, self-aligning floating sleeve bearings are used so that the tubular bore can constantly align itself with the shaft, minimizing wear on the shaft, bearing, and motor.
While the floating sleeve bearing must be free to align itself with the shaft, the bearing must be restricted from rotating with the shaft. One common design incorporates a bearing with a spherical exterior that is seated in a spherical bearing pocket. To prevent rotation of the bearing, a spring force is applied to the exterior of the bearing, causing friction between the bearing and the pocket. The spring force applied creates enough friction to prevent rotation of the bearing in the pocket, while still allowing the bearing to align itself with the shaft.
Another common design involves cutting grooves into the exterior of the spherical bearing and aligning those grooves with ribs in the bearing seat. The bearing is thus free to align itself with the shaft, while the ribs and grooves prevent rotation.
Yet another design involves machining flat portions on the exterior of an otherwise round or spherical bearing and placing the bearing in a seat designed to engage the flat portions and prevent rotation. Alternatively, the bearing could be press-fit into the seat such that during the press-fitting, the interference between the bearing and the seat deforms the bearing, creating flat portions that engage the seat and anti-rotate the bearing. An example of this design is disclosed in U.S. Pat. No. 4,368,931 issued Jan. 18, 1983.